Diagnostic Aids
Perform this test when directed by QUICK TEST procedure. This CIRCUIT TEST is intended to diagnose:
- Wiring harness circuits (EGRT and SIGRTN).
| Circuit | PCM Pin No. | (1) BOB Pin No. | Wire Color | ||
|---|---|---|---|---|---|
| EGRT | 8 | 25 | White/Pink | ||
| SIGRTN | 21 & 29 | 46 | White/Black | ||
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1) Check EGRT Sensor Resistance Allow engine to cool. Start engine. Use a thermometer to monitor engine coolant temperature. Warm engine to temperature specifications shown in EGRT SENSOR RESISTANCE SPECIFICATIONS table. Turn ignition off. Disconnect EGRT wiring harness connector. Measure resistance between connector terminals. If resistance is correct, go to next step. If resistance is not correct, replace EGRT sensor.
| Coolant Temperature °F (°C) | M Ohms |
|---|---|
| 68-120 (20-49) | 2.25-2.55 |
| 130-148 (55-65) | 1.75-2.25 |
| 150-165 (66-74) | 1.40-1.75 |
| 168-190 (76-88) | 1.00-1.40 |
2) Check EGRT Circuit Turn ignition off. Install Breakout Box(007-00033), leaving PCM disconnected. Leave EGRT wiring harness connector disconnected. Disconnect in-line connector located on right side of intake plenum. Measure resistance between breakout box test pin No. 25 and EGRT terminal of EGRT in-line connector. Measure resistance between EGRT terminal of EGRT in-line connector and EGRT terminal of EGRT sensor harness connector. Resistance should be 5 ohms or less. Reconnect in-line connector. Measure resistance between breakout box test pin No. 25 and ground. Resistance should be 10,000 ohms or more. If resistance is as specified, go to next step. If resistance is not as specified, repair or replace circuit.
3) Check SIGRTN Circuit Leave ignition off and EGRT wiring harness connector disconnected. Measure resistance between breakout box test pin No. 46 and SIGRTN terminal of in-line connector. Measure resistance between SIGRTN terminal of in-line connector and SIGRTN terminal of EGRT wiring harness connector. If both resistance values are 5 ohms or less, replace PCM. If either resistance value exceeds 5 ohms, repair circuit as necessary.